'Hero' armed citizen in mall stopped shooter: Police chief

At least three people were killed and two others were injured in a shooting at an Indianapolis-area shopping mall on Sunday evening, police said.

Multiple people called 911 at around 6:05 p.m. local time to report an active shooter at the Greenwood Park Mall in Greenwood, Indiana, some 14 miles south of Indianapolis. An unidentified gunman had walked into the mall's food court and opened fire, according to Greenwood Police Chief Jim Ison.

Olivia Harding said she was at the Old Navy in the mall with her mom when they heard four gunshots and initially thought the nearby carousel was breaking down. But then they heard six more shots.

"I told my mom instantly to get down," Harding recalled in an interview with ABC News on Sunday night.

A person who was lawfully armed -- identified as a 22-year-old man from Bartholomew County -- shot and killed the gunman, according to Ison.

"The real hero of the day is the citizen that was lawfully carrying a firearm in that food court and was able to stop that shooter almost as soon as he began," Ison told reporters during a press conference on Sunday night.

Greenwood Mayor Mark Myers also confirmed that the suspect was "shot by an armed individual," whom he called a "good Samaritan."

"This person saved lives tonight," Myers said in a statement late Sunday. "On behalf of the City of Greenwood, I am grateful for his quick action and heroism in this situation."

The victims include four females and one male. Among the injured is a 12-year-old girl whose parents brought her to the hospital with minor injuries after the shooting. The second injured victim was hospitalized and in stable condition as of Sunday evening, according to the police chief.

The suspect, who appears to have used a long-gun rifle with several magazines of ammunition, has not yet been identified, nor has a motive been determined, Ison said.

While the deadly shooting remains under investigation, Ison said there is currently no ongoing threat and SWAT teams have cleared the mall.

Indiana Gov. Eric Holcomb said Indiana State Police are assisting local authorities in the incident.

"Lives were lost today, and I'm thinking about all the victims of this horrible incident, now and in the days and weeks to come," Holcomb said in a statement via Twitter late Sunday.

ABC News' Ebony Peeples and Darren Reynolds contributed to this report.